The present invention is directed to biological methods, processes, microorganisms, and apparatus for producing products, materials, intermediates, and the like such as organic acids, single cell protein ("SCP"), hydrogen, alcohols, and organic acid salts from the waste gas streams of certain industrial processes and more particularly concerns a process utilizing continuous gaseous substrate fermentation under anaerobic conditions to accomplish this conversion.
The conventional procedure for producing organic acids, alcohols, hydrogen and organic acid salts is chemical synthesis of petroleum-derived feedstocks. The rapidly escalating cost of petroleum has generated considerable interest in producing these valuable commodities by fermentative processes that utilize renewable or waste materials as the feedstock. Single cell protein is produced as a by-product of the fermentations to be used as an animal feed supplement.
There is also growing concern over the massive amounts of atmospheric pollutants and greenhouse gases produced by conventional industrial processes. The Environmental Protection Agency recently estimated that over six million metric tons of carbon monoxide and nearly four million metric tons of hydrogen were discharged annually by the industrial complex. A substantial portion of this waste carbon monoxide and hydrogen is the result of carbon black manufacture and coke productions roughly 2.6 million metric tone of CO and 0.5 million metric tons of H.sub.2. Large amounts of carbon monoxide or hydrogen are also produced by the ammonia industry (125, 144 metric tons of CO in 1991), petroleum refining (8 metric tons per thousand barrels), steel mills (152 pounds per metric ton of steel produced), and sulfate pulping of wood (286 pounds per ton of pulp). In 1991, the adipic acid industry generated 40,773 metric tone of carbon monoxide that was burned for fuel value or flared. In many cases, these gases are discharged directly to the atmosphere, placing a heavy pollution burden on the environment.
Typically, the waste gases from the manufacture of industrial products are released at low pressures and temperatures. Current technology cannot utilize these dilute gases tinder such conditions. Adapting existing technology to separate and recover hydrogen or carbon monoxide from these waste streams would be expensive and impractical.
In light of the foregoing, there is a need for a cost effective and practical method, microorganism, and apparatus for utilizing the above-described waste gases and for producing products, materials, intermediates and the like such as organic acids, alcohols, hydrogen and organic acid salts by other than chemical synthesis of petroleum derived feedstocks.